(a) Field of the Present Invention
The present invention relates to a novel (meth)acrylic or norbornene carboxylate compound having a pendent group with dicyclohexyl bonded thereto, a process for the preparation thereof, a chemically amplified polymer synthesized therewith, and a photoresist composition for ArF comprising said polymer, with high resolution and excellent etching resistance.
(b) Description of the Related Art
As semiconductor devices become highly integrated, ultra-fine patterns having sub-quarter micron dimensions are needed. For this, the wavelengths of light sources used in patterning have become shortened according to Rayleigh's rule, such as from 436 nm (g-line) and 365 nm (1-line) to 193 nm (ArF), 157 nm (VUV), and 248 nm (KrF). In prior arts, however, in order to obtain a pattern size for devices having capacities exceeding 1 Gbit, general resist materials had to be used at 248 nm. Therefore, new resists capable of functioning at a shorter wavelength of 193-nm have been continuously developed to satisfy the requirements of fine resolution.
As is widely known, polymers for use as an ArF-resist material are classified according to their structure into three forms, polyacrylate, cycloolefin-maleic anhydride copolymer, and polynorbornene. Of them, the cycloolefin-maleic anhydride copolymer (COMA)-type resists are useful in view of more or less lithographic performances (pattern collapse, line edge roughness, SEM beam contraction, etching resistance, etc.) However, said COMA-based photoresists cause unsatisfactory results in resolution, especially in terms of line density and space pattern, due to the hydrolysis of maleic anhydride (MA). Also, photoresists comprising conventional COMA do not exhibit sufficient resistance and consequently a dry etching process is still difficult.